Method of treating contact lenses

ABSTRACT

Treatment of contact lenses by an effective amount of bendazac, 5-hydroxybendazac or a salt thereof with a physiologically acceptable base.

This is a continuation of co-pending application Ser. No. 077,620 filedon July 24, 1987, now abandoned.

This invention relates to a method of treating contact lenses.

More particularly, it relates to the use of compound which inhibitproteins sedimentation from lacrimal fluid on contact lenses, preferablyof the soft type, and neutralize possible protein sediments withoutsubstantially affecting mucus secretion by mucous membranes.

It is known that soft contact lenses represent a progress in comparisonwith rigid ones in that they do not cause and do not transmit mechanicaltraumas to the eye. Nevertheless, they have the drawback of quicklyundergoing opaqueness because of protein sediments from lacrimal fluid,the amount and nature of which are widely different from individual toindividual. Moreover, very often, the said protein sediments promote akeratoconjuctival process of sensitization which causes cornealirritation phenomena.

Several washing techniques have been suggested for removing the abovesaid sediments, preferably by means of solutions containing surfactantsor enzymes.

These techniques, however, do not allow removing all the sediments andleave some residue which causes the above mentioned drawbacks.

Therefore, a compound is still in great demand capable of completely, orto a great extent, preventing the formation of protein sediments oncontact lenses and which anyhow is capable of preventing the smallsediment, so formed, from having sensitization properties.

It has been now found that the so called "Aspirin-like" compounds, thatis the non-steroid antiinflammatory acid compounds, such as salicylicacid, phenylbutazone, ibuprofen and mefenamic acid, posses suchproperties.

These compounds, however, substantially reduce the amount of mucussecreted by mucous membranes. Since mucus plays a very important role inprotecting the eye, the so called "Aspirin-like" compounds result to becontraindicated for contacting the eye.

Furthermore, it has been now surprisingly found that bendazac,5-hydroxy-bendazac and their salts with inorganic or organicphysiologically acceptable bases, inhibit sedimentation of proteins fromlacrimal fluid on contact lenses and neutralize the irritativeproperties of possible protein sediments without substantially affectingthe secretion of mucus by mucous membranes.

It is, therefore, an object of this invention to provide a method oftreating contact lenses, preferably of the soft type, comprisingcontacting a lens with an effective amount of bendazac,5-hydroxy-bendazac or salt thereof with an organic or inorganicphysiologically base.

The compounds of formula: ##STR1## where R is H (bendazac) or OH(5-hydroxy-bendazac), and their salts with inorganic and organicphysiologically acceptable bases, are already known, for example fromthe Italian patent application Nr. 49,790 A/81 of Nov. 27, 1981 andEuropean patent application Nr. 191,520 of Jan. 29, 1986 that describetheir use as anticataract agents.

Examples of suitable bases are the alkali metals such as sodium andpotassium, the aliphatic amines, the basic aminoacids such as lysine andarginine, and the like.

Before being contacted with the lens, a compound of formula I or aphysiologically acceptable salt thereof is preferably dissolved into aliquid.

The contact time of the solution comprising a compound of formula I or aphysiologically acceptable salt thereof with a lens shall, of course,vary depending on the compound and the type of solution used. Forinstance, such time will be at least one hour in the case of detergingor wetting solutions, whereas it will be a few minutes in the case ofrinsing solutions.

Another object of this invention is to provide the use of a compound offormula I or of a physiologically acceptable salt thereof for preparingsolutions for the treatment of contact lenses.

The said solutions are prepared by dissolving a compound of formula I ora physiologically acceptable salt thereof in a non-toxic solvent whichis compatible with both the said compound and the lens and which issuitable for undergoing sterilization. Preferably, the said solventconsists of purified or distilled sterile water.

The solutions of this invention may also comprise other ingredients, thenature and amount of which vary depending on the type of solution to beprepared; this may indeed be of a wetting, deterging, disinfecting orrinsing type.

In the case of individuals in which the compound of formula I used orits physiologically acceptable salt is not capable of inhibiting up to100% of the formation of protein sediments, the solutions preparedaccording to this invention are used together with solutions comprisingsurfactants or enzymes, or they themselves comprise surfactants and/orenzymes. However the time before the lens becomes opaque is much longerin the case of the lens thus treated than that observed, for the sameindividual, when the lens is treated with surfactants and/or enzymesalone and even the probability of the arising of corneal irritation isvery reduced compared to that of the usual treatments.

Examples of other suitable ingredients are preservatives, salts forregulating the osmotic pressure, antiseptics, disinfectants,antioxidants and buffers.

Said solutions may be easily prepared according to usual techniqueswhich are well known to the people skilled in this art and comprisesimple operations such as dissolving and sterilization.

A further object of this invention is to provide aqueous solutionscomprising an effective amount of a compound of formula I or of aphysiologically acceptable salt thereof, which are suitable for wetting,deterging or rinsing contact lenses.

Typical examples of solutions according to this invention comprise acompound of formula I or a physiologically acceptable salt thereof andat least a disinfectant, a surfactant and/or an enzyme.

Examples of suitable disinfectants, surfactants and enzymes arechlorhexidine gluconate, octylphenoxyoctanol and papain, respectively.

Preferably the solutions according to this invention comprise from 0.05to 2% of bendazac, or of 5-hydroxy-bendazac, or the corresponding amountof a salt with a physiologically acceptable organic or inorganic base.

The following examples are given to illustrate this invention without,however, limiting it in any way.

EXAMPLE 1

    ______________________________________                                        Wetting solution                                                              100 ml contain:                                                               ______________________________________                                        Bendazac sodium salt                                                                             0.25        g                                              Hydroxy ethyl cellulose                                                                          0.4         g                                              Polyvinyl alcohol  1.4         g                                              Thymerosal         0.004       g                                              Sodium edetate     0.20        g                                              Sodium chloride    0.75        g                                              Boric acid or borax to                                                                           pH 7.4                                                     Sterile distilled water q.s. to                                                                  100         ml                                             ______________________________________                                    

EXAMPLE 2

    ______________________________________                                        Wetting solution                                                              100 ml contain:                                                               ______________________________________                                        5-hydroxybendazac  0.25        g                                              Hydroxy ethyl cellulose                                                                          0.4         g                                              Polyvinlyl alcohol 1.4         g                                              Thymerosal         0.004       g                                              Sodium edetate     0.20        g                                              Sodium chloride    0.65        g                                              Anhydrous Sodium sulfite                                                                         0.15        g                                              1 N Sodium hydroxide to                                                                          pH 6.5                                                     Sterile distilled water q.s. to                                                                  100         ml                                             ______________________________________                                    

EXAMPLE 3

    ______________________________________                                        Deterging solution                                                            100 ml contain:                                                               ______________________________________                                        Bendazac sodium salt                                                                             0.25        g                                              Polivinyl alchol   1.4         g                                              Thymerosal         0.004       g                                              Sodium edetate     0.20        g                                              Sodium chloride    0.75        g                                              Octyl phenoxy ethanol                                                                            0.35        g                                              Boric acid or borax to                                                                           pH 7.4                                                     Sterile distilled water q.s. to                                                                  100         ml                                             ______________________________________                                    

EXAMPLE 4

    ______________________________________                                        Deterging solution                                                            100 ml contain:                                                               ______________________________________                                        5-hydroxybendazac       0.25    g                                             Polyvinyl alcohol       1.4     g                                             Thymerosal              0.004   g                                             Sodium edetate          0.20    g                                             Sodium chloride         0.65    g                                             Anhydrous Sodium sulfite                                                                              0.15    g                                             Octyl phenoxy ethanol   0.35    g                                             1 N Sodium hydroxide to pH 6.5                                                Sterile distilled water q.s. to                                                                       100     ml                                            ______________________________________                                    

EXAMPLE 5

    ______________________________________                                        Disinfecting solution                                                         100 ml contain:                                                               ______________________________________                                        Bendazac sodium salt    0.25    g                                             Sodium chloride         0.75    g                                             Thymerosal              0.001   g                                             Chlohrexidine gluconate 0.005   g                                             Sodium edetate          0.1     g                                             Polysorbate 80          0.05    g                                             Boric acid or borax to  pH 7.4                                                Sterile demineralized water q.s. to                                                                   100     ml                                            ______________________________________                                    

EXAMPLE 6

    ______________________________________                                        Disinfecting solution                                                         100 ml contain:                                                               ______________________________________                                        5-hydroxybendazac        0.25   g                                             Sodium chloride          0.65   g                                             Anhydrous Sodium sulfite 0.15   g                                             Thymerosal               0.001  g                                             Chlorhexidine gluconate  0.005  g                                             Sodium edetate           0.1    g                                             Polysorbate 80           0.05   g                                             Sterile demineralized water q.s. to                                                                    100    ml                                            ______________________________________                                    

EXAMPLE 7

    ______________________________________                                        Solution for rinsing or thermal disinfection                                  100 ml contain:                                                               ______________________________________                                        Bendazac                0.25    g                                             Sodium chloride         0.75    g                                             Thymerosal              0.001   g                                             Sodium edetate          0.1     g                                             Boric acid or borax to  pH 7.4                                                Sterile demineralized water q.s. to                                                                   100     ml                                            ______________________________________                                    

EXAMPLE 8

    ______________________________________                                        Solution for rinsing or thermal disinfection                                  100 ml contain:                                                               ______________________________________                                        5-hydroxybendazac       0.25    g                                             Sodium chloride         0.65    g                                             Anhydrous Sodium sulfite                                                                              0.15    g                                             Thymerosal              0.001   g                                             Sodium edetate          0.1     g                                             1 N Sodium hydroxide to pH 6.5                                                Sterile demineralized water q.s. to                                                                   100     ml                                            ______________________________________                                    

EXAMPLE 9

    ______________________________________                                        Wetting solution                                                              100 ml contain:                                                               ______________________________________                                        Bendazac lysinate  0.4         g                                              Hydroxy ethyl cellulose                                                                          0.4         g                                              Polyvinyl alcohol  1.4         g                                              Thymerosal         0.004       g                                              Sodium edetate     0.2         g                                              Sodium chloride    0.75        g                                              Boric acid or borax to                                                                           pH 7.4                                                     Sterile distilled water q.s. to                                                                  100         ml                                             ______________________________________                                    

A first experiment has been carried out on six individuals wearing softcontact lenses and specifically selected because they produced every 5-6days such an amount of sediments on the said lenses that they had totreat their lenses daily with a deterging composition containing asurfactant, and weekly with a composition containing a proteolyticenzyme.

These individuals stopped using the composition containing a proteolyticenzyme. For a period of three months they regularly dipped their lensesin a solution according to example 9 every night after the usualdeterging and disinfecting treatment. More particularly, the lenses werekept in the above solution overnight.

In the course of the entire three months period, all six individuals didnot need to clean their lenses with any composition containing aproteolytic enzyme.

A second experiment has been carried out on ten individuals whose softcontact lenses showed appreciable sediments easily detectable, observingthe lenses on a black background through a 7-fold magnification. Theseindividuals used the solution according to example 8 by contactingdirectly the worn lenses in situ with two drops of the said solution 4times a day.

The regular use of the said solution for 14 consecutive days caused, inall ten individuals, disappearance or substantial reduction of thesediments on the lenses.

What is claimed is:
 1. A method of inhibiting protein sedimentation fromLacrimal fluid on a contact lens and neutralizing irritative effect ofexisting protein sediments without substantially affecting mucussecretion by mucous membranes of the contact leans wearer wherein saidlens is contacted with an effective amount of a composition comprisingbendazac, 5-hydroxy-bendazac, or a salt thereof with an inorganic ororganic physiologically acceptable base, and a physiologicallyacceptable carrier said contact occurring prior to insertion into theeye.
 2. The method, as in claim 1 wherein the contact lens is a softcontact lens.
 3. The method, as in claim 1 wherein the effective amountof bendazac or 5-hydroxy-bendazac is 0.05-2% or the corresponding amountof the salt thereof.
 4. The method, as in claim 1 wherein thephysiologically acceptable base is selected from the group consisting ofsodium, potassium, aliphatic amines and basic aminoacids.
 5. The method,as in claim 1 wherein the polysiologically acceptable carrier is water.6. The method, as in claim 1 wherein the composition further comprisessurfactants or enzymes.
 7. The method, as in claim 1 wherein thecomposition further comprises one or more of the group consisting ofpreservatives, salts for regulating osmotic pressure, antisepticsdisinfectants, antioxidants and buffers.
 8. The method, as in claim 1wherein the contact lens is contacted with the composition for at leastone hour.
 9. The method, as in claim 6 wherein the enzyme comprisespapain.
 10. The method, as in claim 6 wherein the surfactant comprisesoctylphenyoryoctanol.
 11. The method, as in claim 7 wherein thedisinfectant comprises chlorhexidine gluconate.
 12. The method, as inclaim 1 wherein the composition comprises, in 100 mls of distilled water

    ______________________________________                                        Bendazac lysinate      0.4     g                                              Hydroxy ethyl cellulose                                                                              0.4     g                                              Polyvinyl alcohol      1.4     g                                              Thymerosal             0.004   g                                              Sodium edetate         0.2     g                                              Sodium chloride        0.75    g                                              Boric acid or borax to pH 7.4.                                                ______________________________________                                    